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M. PREUDENB-ERG. AUTOMATIC TELEPHONE SYSTEM.

No. 587,435. Patented Aug. 3,1897.

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M. FREUDENBERG. AUTOMATIC TELEPHONE SYSTEM.

No. 587,435. Patented Aug. 3,1897.

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M. FREUD'B'NBERG. AUTOMATIC TELEPHONE SYSTEM.

No. 587,435. Patented Aug. 3,1897.

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MFRBUDENBERG. AUTOMATIC TELEPHONE SYSTEM.

No. 587,435. Patented A 3, 1897.

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M. FREUDENBERG. AUTOMATIC TELEPHONE SYSTEM.

No. 587,435. Patented Aug. 3,1897.

@m ubyb UNITE STATES PATE T QFFICE,

MOISE FREUDENBERG, OF PARIS, FRANCE, ASSIGNOR TO ROGER \VILLIAMS VVALLAOE, OF LONDON, ENGLAND.

AUTOMATIC TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 587,435, dated August 3, 1897.

A Application filed October 22, 1896. Serial No. 609,721. (No model.)

To all whom, it may concern:

Be it known that I, MOISE FREUDENBERG, a citizen of the Empire of Russia, and a resident of Paris, (Seine,) in the Republic of France, have invented certain new and useful improvementsin telephonic self-comm utators permitting the suppression of employees in the offiee connecting the subscribers together, of which the following is a full, clear, and lo exact description.

This invention relates to anew or improved system of automatic apparatus for enabling a subscriber to a telephone-exchange to obtain communication with another subscriber to the same exchange directly without having to ask a central-office operator to make the desired connection.

Before explaining in detail the different elements employed in the new or improved system of automatic telephone-switching a general indication will be given of the system as a whole and the mode of connecting the elements which compose it.

At each subscribers is a telephonic appa- 2 5 ratus connected with a switch at the central office, the connection being effected between the subscribers apparatus and the centraloffice switch by means of two wires, for it will be supposed that the telephone-exchange is 0 established for working by means of two wires,

the return not being effected by the earth.

The switch at the central office correspond ing with each subscribers apparatus is divided into a certain number of sectors ten, 5 for exampleand each of these sectors is connected (as will be explained below) with a carriage forming part of a particular group of carriages at the central office. Thecentral office has then, besides the switches, ten

' 40 groups of carriages, and each subscriber has strips underlying the path which the carriage 5o follows, and can stop itself in contact with one of these strips, thereby putting the subscriber to whom the carriage belongs into communication with him' whose line is connected with the designated strip.

At the central office there are as many strips as subscribers, and the wires of each subscribers line are connected with the corresponding strip in one of the carriage groups at the central office.

If it be supposed for a moment that the exchange has ten thousand subscribers, these may be divided into groups of one thousand, which give ten groups of subscribers, and in each of the groups of carriages before referred to are placed one thousand strips, each of which corresponds with one of the subscribers of the group and is connected with his station, as before mentioned.

It will seem then that if any subscriber wishes to talk with another subscriber hav- 7o ing a number belonging to the third group say, for example, subscriber 2,846 -he will so act as by proper currents to place his switch on the third sector in order to connect himself through said switch with the carriage of the third group which belongs to him. This carriage, being put in motion by currents of the proper direction, passes at a given point over the strip corresponding with the eight hundred and forty-sixth subscriber of the third group. At this moment communication is established between the two subscribers, and they can then converse.

As may be seen from the preceding explanation, the principle upon which is based the present new or improved system of automatic telephone-switching consists in the division of subscribers into distinct groups, each subscriber having at the central office a special switch, as, many carriages as there'are '90 groups in the system, and a special device, which has hereinabove been called a strip, placed in a determined groupthat is, in the group to' which the subscriber belongs.

In order to make the following explanation 5 as clear as possible, an automatic telephoneswitch apparatus in accordance with the invention is illustrated by way of example in the accompanying drawings.

As thus illustrated, various device-shifting I00 electromagnets at the subscribers station and at the central office are shown placed in derivations of the main-line circuit, when in practice they would be placed in local circuits and be controlled by relays placed in the main-line branches in which the electromagnets are located, as shown. This arrangement permits the production of very considerable mechanical effects with feeble cur rents. Should the available main-line currents suffice (by reason of their own strength or the easy operation of the mechanism) to effect the shifting of the devices without the aid of local currents, these might of course be dispensed with.

Figure 1 is a perspective view of the telephone apparatus at a subscribers station. Fig. 2 is a diagram showing the details ofthe different parts of the apparatus which is shown in perspective in Fig. 1. Fig. 3 is a plan view of one of the switches at the central oflice, each subscribers station being connected with a switch which may be identical with that shown in this figure. Fig. 4 is a section on line 1 2 of Fig. Fig. 5is aplan view in detail of one of the centrahoffice carriages, which may belong to any group and any subscriber. Fig. 5 is a detail side elevation of mechanism for controlling the m ovements of the carriage. Figs. 6 and '7 are vertieal sections showing the different positions occupied by one of these carriages. Fig. 8 is a section on line 3 i of Fig. '6. Fig. 9 is a diagram illustrating the electrical connections between a subscribers station, the corresponding switch, and the carriage corresponding with sector No. 1 of the switch. Fig. 10 is a vertical section showing the interconnection of the strip-segments belonging to the same subscriber when the carriages of a single group, instead of being disposed in one horizontal plane, are placed 011 several parallel horizontal planes. Figs. 11 and 11 are diagrams showing the whole of an in stallation in accordance with the present invention for twenty subscribers.

The automatic telephone switch apparatus of the present invention may be considered under four distinct heads:

First. The substation or home apparatus at a subscribers, (all the subscribers stations being identical with one another.)

Second. One of the switches placed at the central office and connected directlywith one of the substations, (all the switches being identical with one another.)

Third. One of the carriages which is connected with one of the switch-sectors, (all the carriages being identical with one another.)

Fourth. The general arrangement with examples referring to communication (a) be tween two subscribers of the same group and (b) between two subscribers of different groups.

1. The sub-station apparatus-J11 considering the apparatus at the subscribers station no account will be taken of the telephone itself, which may be of any suitable description, although in the drawings the telephones are supposed to be of the Ader system, generally used in Exchanges in France. The additional devices employed for applying the new or improved automatic switching in conjunction with this system of telephones will now be described in order.

The various parts of the substation apparatus are placed in a box A above and behind the subscribers telephones, the box A being shown in perspective in Fig. 1. They comprise a battery A a switch A a second switch A a polarized electromagnet A and a count ing system of three wheels A A Fig. 2.

The switch A, is formed of a flat disk which carries ten metallic contacts a, between which insulated blocks a, are interposed. At the center of the disk is mounted on a pivot an arm provided at its end with a button a by which the arm can be turned from left to right about its center (1 in such manner as to perform a complete rotation about this center.

The arm a is connected by a wire 1. with the line-wire 2, going from the substation to the central office, and all the metallic sectors to of the switch are connected by the wire 4 with the positive pole of the battery A whose central element is connected by the wire 5 with the return-wire 3 from the central oflice to the snbscribers. By this mode of connection it will be seen that if the arm a is turned about its center it will come successively in contact with each of the sectors and that every time a contact of this kind takes place a positive current from the battery A will pass by the wire 4: to the switch-point opposite the arm a and thence through the said arm and the wires 1 and 2 to the central office, returning from said office by the wires 3 and 5 to the battery A. Every time therefore the subscriber turns the arm a, through an are equal to a sector of the switch he will send to line a positive current. The arm a is of course insulated from the body of the switch.

The switch A (the second switch before mentioned) is composed of a disk divided into eight sectors b 11* b b Z), Z), b At the center of this disk is pivoted an arm Z), provided with a button Z) for turning the arm from left to right completely around the switch-disk.

Of the eight sectors which compose the switch just spoken of the first, 12 is made of insulating material, and it is on this sector that the arm I) rests when the apparatus is in repose. The word Repose may be inscribed above the sector 6 and also above the first sector of the switch A so that the subscriber can see at a glance whether the parts of his apparatus are in the positions which they should normally occupy.

The four sectors [1 I), Z2 and Z), are c011- nected by the wire (3 with the negative pole of the battery A The sectors 19* and b are insulated. The sector Z), is connected by the wire 7 with the polarized electromagnet A The arm I) is connected by the wire 8 with the wire 1 and by it with the line-wire 2, which goes from the subscribers station to the central office.

So long as the arm I) is on the insulatingpoint 79 theapparatus is in repose. By carrying the arm b from the point 1),, to the point 11* it is made to pass over the point b on which the arm should not stop but only pass over it. The passage of the arm I) over the point 11 has the effect of sending a negative current to line, the conducting-point b being connected with the negative pole of the battery A, by the wire 6. The current from this negative pole on reaching the point 1),, passes by the arm 6 and wires 8 and 1 to the linewire 2. It returns from the central office by the Wire 3 and finally reaches the battery A by the wire 5. The same phenomena are produced when the subscriber passes the arm I) from 19* to the point 17 and from the point I), to the point 12 in consequence of the arm rubbing over the points 6, and 5 which are connected with the negative pole of the battery.

When the arm I) is in contact with the point 7),, the line is put in communication with the polarized electromagnet A since the point I), is connected with the electromagnet by the wire '7 and the arm 17 is connected to line by the wire 1. By bringing the arm I) from the point 12 onto its point of repose b, it will be made to rub over the point b ,which will send a negative current, as in the case of the points 19 1),, and 12 It will be seen then that a complete revolution of the arm I) of the switch A will have the effect of sending four negative currents and of putting th positive electro- 1nagnetA toline atagiven oment, (intermediate the third and fourth negative currents.) The function and effect of each of these currents will be seen later when consideration is given to the communications.

The three-wheel counter (represented in Fig. 2) is of the kind employed to register the number of turns. It consists, essentially, of a primary disk A on the axis of which is fixed a ratchet-wheel O, that can be operated by the polarized electromagnet A 4 through the pawl 0, this latter being connected by the arm 0' with the armature O of the electromagnet. A stop'pawl controls the movement of the ratchet-wheel O,which sho uld only turn through an are equal to one tooth at each retraction of the armature C after each attraction of the latter by the polarized electromagnet A.

The disk A or it may be the box outside the disk A carries the figures 0 to 9, and opposite each of these figures at the margin of the disk is formed a notch that may engage the arm 0 which can be maneuvered by hand and which is pivoted at its center 0 This arm is analogous, as also are the arms 5 and Q of the switches A and A to those in use in switches of the Breguet kind that.is to say, they can engage notches in the margins of the disks over which they are placed.

identical with the disk A but it is not operated (as the latter is) by the polarized electromagnet A The disk A turns one division every time the disk A, makes a complete revolution.

The mode of shifting the disk A by the disk A is not shown, for there is nothing peculiar in this point, and use may be made of any kn own or suitable arrangement wherebyin turn-counters the tens-wheel is shifted by the units-wheel.

What has just been said about the wheel A applies fully to the wheel A which corresponds with the hundreds-wheel of a turncounter. Every time the tens wheel A makes a complete revolution the hundredswheel A moves one division. It follows from this that the system of three wheels A A A apart from the arms 0 and the notches at the margins of the wheels constitutes a veritable turn-counter. The three-wheel system is completed by certain electrical arrange ments which will now be considered.

When the hundreds-wheel is at zero in the position shown in Fig. 2, the arm 0 being in the zero-notch, it bears on a conducting-point 0,, which isconnected by the wire 9 with the negative pole of the battery A The arm 0,

itself, which is of course insulated from the body of the apparatus, is connected by the wire 10 with the point 0 on which the arm O, of the disk A bears when this disk is in repose and its arm is in the notch correspond ing with zero. The arm C, of the disk A is itself connected by the wire 11 with a point 0 which issituated like the preceding outside the disk to which it appertains, but in this case between the'zero and one of such diskto wit, of the disk A -when the said disk is in repose. In this position, as shown in Fig. 2, the arm 0 of the disk A does not touch the point 0 To finish the description of the electrical communications of the counter, it is added that the arm 0 of the disk A, is connected with the line-wire by the wire 12.

Such is the nature and arrangement of all the devices at the subscribers station. They serve, as will be explained below, to operate automatically the devices at thecentral office.

2. A subscribers switch at the central 0ffice.All the subscribers stations have apparatus indentical with that described, and each of them is connected by the two linewires 3 and 2 with a switch at the central office. Since all of these central-office switches are alike, it will suflice to explain one of them. It is shown in detail in Figs. 3 aud t. It is composed mainly of a horizontal disk D, of

insulating material, Fig. 4, which carries near its outer edge a ring divided into ten sectors D D D &c., equal to one another, and a smaller sector d, called the reposesector, which is two-thirds of any one of the sectors results from the grouping adopted (by way of example) for the subscribers. In general, the number of the switch-sectors should be equal to the number of the subscribers groups. In the case then of ten groups of subscribers the switches D would have ten sectors.

Each of the large sectors D D D &c., is divided into two parts insulated from each other, and of these parts that marked d d (2 &c., is connected by the wire 12 with an electrom agnet E, responding to positive currents, while the other, m n p, is connected by a wire 13 13 13 the, with one of the groups of carriages, which will be considered later.

To make the drawings simpler, it is supposed, in Fig. 3, that all the parts (Z, d 61 due. of the sectors D D D dzc. are connected electrically with a central wire d, which is itself connected by the wire 12 with the electromagnet E. In practice in constructing the apparatus any suitable mode of establishing the electrical connections could be adopted.

If attention be given to sector D,, it will be seen (in confirmation with what has been said above) that the part (I, of this sector which is insulated from the rest is connected with the positive electromagnet E and that the other part of the sector is connected by a binding-post c, with a wire 13,. In like manner the part of sector D which is not connected with the positive electromagnet is connected by a binding-post c, with the wire 13,, and so on with the others. It should be said in addition that the different sectors D D D,, &c., are insulated from one another and from the body of the disk D. On this disk, concentric with the ring of sectors D D &c., is fixed a continuous ring D, which is connected by a wire 14, Fig. 3, with a polarized electromagnet E, responding to negative currents.

The sector of repose d, which is insulated from the sectors D and D which inclose it, and is two-thirds of one of these sectors, is connected by its outer portion with a wire 15, that, like the wires 13 13 &c., leads away from the switch.

Above the disk D is a movable arm D, carrying two brushes 6 e. The first of these to wit, the brush erubs during the rotation of the arm D over the sectors D D D,, &c., in such manner that when the arm D is over the part (i, of sector D,, for example, the brush e rubs at the same time on this part (I, and on the partm of the sector connected with the wire 13,.

The second brush e, which is placed below the preceding, is intended simply to connect the wire 14 with the ring D. A single wide brush could replace the two brushes, and, in fact, the ring D and brush 6 could be dispensed with, the wire 14 being otherwise connected with the line-wire 2 in any suitable way.

Suppose for a moment that each of the sectors is divided by radii of the disk D into three equal parts on n 1). It will be seen that,

tor D or D or as the case may be.

Fig. 3, the parts (Z, (Z (7,, &c., each cover cX actly a third part of the length of the sector in which it is intercalated that is to say, the length of one of said equal parts; but it should be noticed that it only has half the width of the ring of sectors.

The electromagnet E, which operates, as above mentioned, by means of negativecurrents, acts through its armature upon an arm E, jointed at its opposite end to a second arm E, which carries a pawl F for action upon a ratchet-wheel F, having nincty'six teeth. The retraction of the armature upon the cessation of the current raises the pawl and advances the wheel. The play of the armature of the electromagnet is so adjusted that every time the electromagnet E is traversed by a negative current the pawl advances idly an amount equal to the are formed by three teeth, and when the current ceases the wheel F is advanced through an equal are. This ratchetwheel has at its center, which is hollow, small pawlsf, which act on teeth f, formed on the shaft f which supports the arm D, but it could be fast on the shaft f,, if preferred. This shaft f, terminates at its lower part in a point resting in a step, Fig. 4. By this arrangement it will be seen then that the rotation of t-herwheel F under the action of the pawl F produces the rotation of the shaft f and consequently of the arm D.

The electromagnet E is actuated by positive currents, and when its armature is attracted it depresses the bar G ,which is jointed to the arm G, which carries a pawl G. This pawl G on the retraction of the armature ascends and then acts upon a ratchet-wheel G, which has thirty-two teeth, and the play of the armature of the electromagnet E is so calculated as that the pawl G at each elevation turns the corresponding ratchet-wheel G through an are equal to three teeth. The ratchet-wheel G also, like the ratchet-wheel F, might be fast on the shaftf but, as shown,

it is hollow at its center and carries pawls f, which engage teeth f on the shaft f, of the arm D. Either of the wheels F or G may therefore turn the arm D without carrying the other along. In other words, the two wheels, while independent of each other, can, when required, each turn the shaft f, on which the arm D is fast.

From what has been said it follows that when the electromagnet E is traversed by a negative current the arm D will on cessation of said current turn through an are equal to three ninety-sixths of the complete circumference-that is to say, through one thirtyseeond of a circle-and will make a complete revolution under the influence of thirty-two successive negative currents. With three such currents it will run over a complete sec- VVlien the electromagnet E is traversed by a positive current, on the contrary, the arm D on cessation of the current turns three thirty-seconds of a circle-that is to say, every displacement other side by the wire 18 with the subscribers' of the arm under the influence of the electromagnet E is three times as great as a displacement under the influence of the electromagnet E.

The line-wires from the substation corresponding with the switch are connected as follows: one of them (the wire 2) with the arm D by the wire 14: and the other (the wire 3) with the electromagnets E and E by the wire 15. Such is the complete arrangement of all the devices which constitute any one of the switches placed at the central office and connected with a subscribers station.

3. A carriage for a sector of one of the subscribe-rs switches at the central oyjiee.-In the preceding description of the subscribers switch it is explained that the wires l 13 13 the. lead away from the different sectors of a switch. Each of these wires leads to certain devices which are now to be described and which so control the carriage which in the selected group corresponds with the subscriber as to put it in motion or to stop it, according to the circumstances. It may be recalled that the division of the automatic switch is so made as that each subscriber has a carriage in each group. In the example chosen each subscriber would therefore have ten carriages at the central office.

In Figs. 5, 6, 7, 8, 9, and 10 the carriage arrangements and electrical connections of the different parts with one another and with the switch are shown in detail.

For each group of carriages at the central office is a rotating motor H, which is driven by a battery of accumulators H or any suitable source. The motor transmit-s its motion through pulleys h h to a shaft H, Fig. 5., 011 this shaft is mounted for each carriage a set of bevel-toothed wheels h h. These turn with the shaft H",-but can be shifted lengthwise thereof in such manner that sometimes the wheel h engages-with a' third wheel h,, and sometimes the wheel h engages with the same wheel 71,. Electrom agnet h Figs. 5 and 5, is connected with the wire 13,, and on the return-wire 3. Suitably connected to be operated by the armature of the electromagnet is a ratchet x,engaging a four-toothed ratchetwheel w on the shaft 00, to which is attached the crank or eccentric 00". This crank 50' is connected by link y to one arm y of a pivoted bell-crank lever, whose other arm y" acts at one end of the system of bevel-wheels h h'.

Normally-that is to say, when no current traverses the electrom agnet h -the two bevel- '-wheels h and h arein their middle position and neither of them engages the wheel h WVhen the electromagnet h is traversed by a negative current, it shifts the system of bevelwheels h and h in a direction parallel with the shaft II". The shifting might be made to take place on the cessation of thecurrent. At the first change of the wheels the bevel-wheel h, for example, comes in contact with the middle wheel 71 and puts in motion both said wheel h and the screw H on which the same is mounted. ranged that if it is traversed by a second current the bevel-wheel system h and h i shifted in the opposite direction and thereby brought backto the middle positionthat is to say, to the position in which the wheel h is in contact with neither of the two others. A third current sent through the electromag net effects a shifting in the same direction as the second, but so as that the wheel h now comes in contact with the wheel h The screw H is rotated thereupon in the opposite direction, and in order to bring the system of wheels afterward to their middle position use is made, not of a fourth negative current, but of the mechanical device H Fig. 5, which is formed by a bent lever acting at one end of the said system and having its outer end under the screw H and so placed in the path of the carriage which moves lengthwise of said screw as that when the carriage returns to the starting-point it strikes the end of the bent lever H and brings the system of wheels h h to the middle position, thereby arresting the rotation of the screw.

In the drawings the details of the electromagnet 71 for producing the movements above explainedare shown; but use may of course be made of any known orsuitable arrangement for accomplishing the three movements mentioned.

From what precedes it is seen then that the screw 11,, which is fast in the wheel 72 may either be stationary or turn in one direction or turn in the opposite direction, and that its condition can be controlled by the passage of currents through the electromagnet h The object of the movements will be explained below.

On the screw II is mounted a carriage H which forms the nut for the screw and which consequently is moved horizontally lengthwise of this screw from right to left or from left to right, according to the direction of rotation of the screw. To prevent the carriage from turning wit-l1 the screw, two supports I I, Fig. 5, are provided for retaining it. The carriage proper, H is composed of a platform carrying an index or brush i, which during the travel of the carriage rubs along a band 11, provided at given distances with metallic switch-points i". The brush i is connected by the wire 19 with the subscribers line-wire 2, and the metallic contacts 11 on the band 'i are connectedwith a battery I Fig. 5, which itself is connected by the wires 18' and 18 wit-h the subscribers return-wire 3. On Fig. 9 and in the general views, Figs. 11 and 11 to simplify the illustration the wire 18 is shown as connected directly with the wire 3. The front part of the carriage carries an inclined arm I which is jointed to the carriage and provided at the end with two metal portions and i insulated from each other. This inclined arm I Fig. 6, can turn on its joint 5 and a spring holds it normally slightly in- The electromagnet h is so ar- ICC IIO

clined forward, as indicated in Fig. 6. The metallic portion 2' of the arm is connected with the wire 19, and consequently with the subscribers line-wire 2,while the metallic portion '2' is connected by the wire 20, Fig. 9, with the subscribers return-wire Under the carriages of each group, which are arranged parallel with each other, as indicated in Figs. 11 and 11 are placedin a position at right angles to the paths of the carriages the strips K which are divided into two metallic portions 7c, k insulated from each other. These strips are mounted on vertical bars k and subjected at given distances to the action of springs 70,, which tend constantly to maintain the strips at a certain height. Stops (not represented on the drawings) may be used to arrest the strips at the desired height, the springs forcing the strips against the stops. If any carriage H passes above one of these strips, the arm I of the carriage will bear upon the strip and depress it. If at this moment the carriage is stopped, the arm will re main in contact with the strip K; but if, on the contrary, the carriage contin uesits movement the arm I will escape from the strip, as indicated in Fig. 7, and this latter under the action of the spring 7a,, Fig. 4-, will ascend to its original position. It hence follows that any carriage advancing from its startingpoint at the end of the screw II on which it is mounted, will in succession depress all the underlying strips and that these will return to their positions at once on the passage of the carriage under the action of the springs 7.1,.

In Fig. 9 the scheme of communication be tween a subseribers station, the corresponding central-office switch, and the carriage corresponding with one of the switch-sectorsis shown on a larger scale.

As explained above, each subscriber of the exchange belongs to a particulargroup at the central office and has, in this group only,.a strip K. It remains then to explain the mode of connection which exists between the subscribers station and the strip belonging to him at the central office. To aid in this explanation, the strip K in Fig. 9 is shown as belonging to the subscriber whose station apparatus is indicated at A. The two portions of this strip K are connected one by the wire 21 with the subscribers return-wire 3 and the other by the wire 15 with the repose-point in the subscribers switch D. The object of this arrangement will be given below in explaining the connections.

If the automatic switching system should be applied to an exchange having a ver 7 large number of subscribers,ten thousand subscribers, for example, divided into groups of one thousand, it would be necessary to have ten thousand carriages in line in each group; and although the dimensions of the carriages might be very small the shaft H would have to be very long. To avoid this difiiculty, in-

stead of arranging in one horizontal plane all the carriages of the same group they are divided into secondary groups placed in parallel horizontal planes, Fig. 10. In this case the strip of a subscriber instead of being continuous is divided into segments K placed vertically under one another, the different segments being connected by bars L L, so that under the action of a carriage the system composed of all the segments is depressed as if it were a continuous strip. This connection of the segments with one another has for its object to avoid the simultaneous connection of several subscribers with another subscriber.

If the case be taken of a continuous strip not divided into segments, it will be seen that when a strip is depressed by a carriage it is impossible for another subscriber to put his line in contact with it; and it is the same with a strip divided into several segments joined together, as explained above, since they move together as one piece.

In the preceding description it is said that a motor is used for each group, the motor rotating continuously; but of course at the central office instead of providing a motor for each group there may be one motor for the exchange which drives the different shafts H of the groups by means of mechanical gearing, or any number of motors, according to the working of the central office. Having thus described in detail all the elements of the new or improved system of automatic switching for telephone-exchanges,the

comm unications between these diiferentparts will now be explained.

4. General explanation, with cmcmzples, of the system of commtmicazfion.lt should be said at once in the explanation which follows, an exchange is supposed with twenty subscribers divided into groups of two, and, further, it is assumed thatthe carriages in each group are placed, as indicated in Fig. 10, in two parallel horizontal planes, each containing only ten carriages.

To facilitate the description, reference will be made to Figs. 11 and 11 which show the system as a whole, reference being also made to the detail views for the different move ments of the various parts of the system.

As shown in Figs. 11 and 11 the subscribers No. 1 and No. 2 have their respective strips in group No. 1, the subscribers No. 3 and No. 4: in group No. 2, the subscribers No. 5 and No. 6 in group No. 3, the subscribers No. 7 and No. 8 in group No. 4, the sub scribers No. 9 and No. 10 in group No. 5, the subscribers No. 11 and No. 12 in group No. 6, the subscribers No. 13 and No. 1st in group No. 7, the subscribers No. 15 and No. 16 in group No. 8, the subscribers No. 17 and No. 18 in group No. 9, and the subscribers No. 19 and No. 20 in group No. 10. The subscribers No. 1 and No. 2 may then be respectively designated by the fractions 11 and 12,the subscribers No. 3 and No.4 by the fractions 2-1 and 22, and so on, meaning that subscriber No. 4 is the second member of IIO 1 until it reaches the point b the second group. The second strip of the second group, therefore, belongs to him, justas subscriber No. 1 is the first member of the first group, and the first strip of the first group belongs to him, and so on for the others. In the fraction designating a subscriber the numerator designates the group and the denominator the number in order of the subscriber in the group.

In the scheme of connect-ions the connections are shown completely only for subscribers No. 1, No. 2, and No. 10.

First. In explaining the working of the apparatus when the telephonic communication is to be established between two subscribers of the same group reference will be made to stations 1-1 and 1-2.

Second. In explaining the connection of two subscribers of different groups reference will be made to stations 1 1 and 5-2.

The subscriber 1-1 wishing to enter into communication with any subscriber of the exchange should first of .all remove the arm D of the central-office switch from its position of repose. To do this, he should send two negative impulses, which he can do by turning the arm I) of his substation-switch A The arm I) during the movement rubs over the points 19 19*, and h, interposed between the two points mentioned. In rubbing over the points b and b the arm 7) closes the circuit of the electromagnet E through the battery A A negative current leaving the batteryA passes by thewire 6, the point 19 or the arm I), the wire 8, the wire 1, and the Wire 2 to the central office, where it goes by wire 14 to the arm D of the subscribers centralofiice switch, and passing thence by brushes 6 and e to the ring D and wire 14 it enters the electromagnet E. After traversing the coils of this magnet the current goes by wire 15 to line-wire 3 back to the subscribers and returns to the battery A by the wire 5. The circuit of the electromagnet E is thereby closed and this electromagnet is traversed by a negative current, to which it responds, since it is polarized to respond to negative currents. Its armature is attracted and then released, and on its return the bar E is depressed,

' causing the pawl F to turn the ratchet-wheel with both part m and with the ring D.

F through an arc equal to three teeth. Each current turns the switch-wheel through one thirty-second of a circle, and the arm D comes (as a result of the two currents) over the first part m d, of the sector D so that the brush e makes contact with both the point C1 and part m, while the brush 6 makes contact It will be noted that after the arm D has left its position of repose it is impossible for any subscriber to the exchange whatsoever to put himself in communication with the subscriber to whom the switch in question belongs, for the strip corresponding with this subscriber is connected by the wire 15 with the reposepoint (I, and this, by the movement of the arm D, is no longer in electrical connection with the line. After the arm D has left the position of repose the subscriber 1-1 who wishes to talk should connect with the group of the subscribers with whom he Wishes to put himself in communication. In the example selected it is a subscriber of the first group who is indicated by the fraction 1-2. In such case the subscriber 1-1 does not have to move the arm D to another sector of the switch, since the arm is already on the sector desired-the first. It would not be the same if the subscriber to whom the subscriber 1-1 might Wish to talk were in a group other than the first. In the latter case, as will be seen when explanation is given of communication between the subscribers 1-1 and 5-2, the subscriber 1-]. would have to manipulate the arm a of his home switch A in such manner as to bring the arm D of his central-office switch D on the fifth sector. To repeat, the transfer of the arm D from one sector to another is produced by manipulating the home switch A and in the example chosen the subscriber does not have to trouble himself to shift the arm D to another sector, since it is already on the desired sector. The subscriber 1-1 then does not'have to select the group in which the subscriber 1-2 is located, because the arm D of the switch of subscriber 1-1 has already come, under the influence of the first negative current, in contact with the sector No. 1, which is connected with the group to which the subscriber 1-2 belongs. The arm D of the calling subscribers switch being then in contact with the sector corresponding with the group in which is located the strip of the subscriber to be called, it suffices for the subscriber 1-1 to advance his carriage in group 1 until it makes contact with thesecond strip of the group, which strip corresponds with the subscriber 1-2. In order to move the carriage forward, the subscriber 1-1 manipulates the arm 0 of the first disk A, of the turn-counter by turning it in the direction of the arrow and placing it in the notch corresponding with the unitnumber of the subscriber-that is, in the example selected, in the notch No. 2. The manipulation of the arm 0 of the counter is now ended, for the subscribers number neither contains tens nor hundreds.

- It would have been otherwise if instead of.

considering a system of self-switching for twenty subscribers divided into ten groups of two a system had been taken of ten thousand subscribers divided into ten groups'of one thousand. In that case, apart from the indication of the group, certain subscribers would have had three or two figures in the numbers by which they would be desinated. So it would be if the subscriber 2-846 or 3-846 were taken as an example. He would be in the third group and possess strip No. 84:6. In case the subscriber 1-1 wishes to talk with subscriber 2-846, he would have to manipulate first his home switch A to S6",

lect the group, as explained below, and then his turn-counter so as to place the arm 0, of the disk A, in the notch No. 6, the arm 0, of the disk A, in the notch No. a, and the arm 0, of the disk A in notch No. 8. Apart from the positions of the arms C, of the turn-counter the following explanation of what is to be done with reference to the subscriber 12 is as applicable to the case of subscriber 3S46 in an exchange having ten thousand subscribers as to said subscriber 1-H in an exchange of twenty subscribers. The subscriber 11, after placing the arm C, of the disk A, in notch No. 2, manipulates anew the arm I) of the home-switch A so as to shift it from the point 5,, onto the point 1),. In this transfer the armbrubs over the point 1),, which has the effect, as mentioned before, of closing the circuit of the electromagnet E through the battery A,. A negative current traverses then this electromagnet E, and the armature acts as before upon the arm D, but now in such manner as to bring it to the middle part at of the first sector D, for it takes three movements of the arm D for it to complete its passage over a sectorname1y, a first movement to bringitover the portions (1, m, a second to bring it over the portion 77., and, lastly, a third to bring it over a portion 19. The arm D being on the middle portion of the sector, is only in contact with the portion thereof which is connected by the wire 13, with the electromagnet 71 Fig. 5. It has wholly left the part d, of the sector, which is connected with the electromagnet E, Fig. 3. The negative current last mentioned, which when sent by the subscriber 11 shifts the arm D, goes also byway of the sectorDand wire 13, to the electromagnet 72,, returning by wire 18, subscribers return-wire 3, and wire 5 (at the subscribers) to the battery. Gonsequently the circuit of this electromagnet 71. is closed. It responds and brings together, as before explained, the wheel h and the wheel 72,. These wheels intermesh and the screw H, rotates. The corresponding carriage H is advanced, and the brush '5 of this carriage bears upon the first metallic point i of the band 11. Through this contact the brush t' closes the circuit of the electromagnet .A of the subscribers station through the battery 1,. The current from this battery goes from the point 1', brush 2', andwire 19 to the linewire 2, and after arriving over this wire at the subscribers station it passes by the wire 1, arm Z) of the home switch A point 1),, (on which the arm is at this time,) and-wire 7 to the electromagnet A,. After traversing this magnet it returns by the wire 3 and wires 18 and 18, Figs. 3 and 5, to the battery I,. The circuit of the polarized electromagnet A is then traversed by a positive current, for the battery I, can only send positive currents.

The electromagnet A,,, being traversed by a positive current, attracts and then releases its armature and turns the disk A, through an are equal to one division, carrying along the arm O,, which has been placed in the second notch of the disk.

The carriage when it touches the switchpoint 2' with its brush t' is preferably just about to bear with its front arm 21,, on the strip K, No. 1, so the positive current from battery I, does not go to the said strip. Under the action of the dynamo the carriage continues to advance; but it only depresses the strip without stopping, and the arm I, leaves the first strip K in the manner shown very clearly in Fig. 7. The subscribers carriage continuing to move on causes the brush 1' to touch the second metallic contact 2', and in the same way as before a second positive current goes to the subscribers station and operates his home magnet A The disk A," is turned then again through an are equal to one division, but in this second rotation the arm 0, of the disk A, makes contact with the point 0,, Fig. 2, and closes the circuit of the electromagnet E of the switch D through the battery A. A negative current now goes from the battery A, by the wire 9, point 0,, arm C, of disk A, and wire 10 to the point 0,, and from this point it passes through the arm 0, of disk A wire 11, and point 0,, thence through the arm 0, of the disk A (which at this time is over the last-mentioned point,) and at length by the wire 12 to the subscribers line-wire 2, Fig. 2. This conducts it to the wire 14: and arm D at the central office. From the arm D" it passes by the brush 6 to the sector D,, thence by the brush 6 to the ring D, and so to the electromagnet E. After traversing this magnet the current returns by wire 15, return line-wire 3, and wire 5 to the battery A,. The electromagnet E, being traversed by a negative current, responds,

and the arm D,'which was on the middle part at of sector D comes over the last part 19 of this sector; but, further, the negative current sent by the battery A to the sector D, divides into two, of which one goes to the electromagnet E and operates as just explained, while the other passes by the Wire 13, to the electromagnet h and returns by the wire 18 and the return line-wire 3. The circuit of the electromagnet is therefore also closed and it is traversed by a current which produces, as explained above, a shifting of the system of two wheels h h in such manner as to place them in the middle position. The wheel 72 no longer meshes with either of the wheels h h. It no longer rotates and the carriage I-I stops. On stopping it is over the strip No. 2 and in contact therewith, for the brush 1' and the arm I are preferably so arranged with reference to one another that at the moment when there is contact between any one of the points i" and the brush 1' the arm I is j ust about to depress the strip K, above which it at that moment may be, and, further, that the arm I makes contact with the strip K during the time which elapses after the contact is broken between the brush i and the point 1 before the carriage is arrested. The negative ourrent which is sent by the electromagnet A,

would go by strip K, No. 2, tothe switch D of subscriber 1 -2 and shift the arm D" thereof, but not so as to clear the repose-point, since for this two negative currents are required. In the position thus attained the carriage H of group No. 1 which belongs to subscriber 1 l is in contact with strip No. 2 of the same group belonging to subscriber 1-2, with whom the subscriber 1-1 wishes to put himself in communication. Now the strip No. 2 which is thus depressed by the arm I of the carriage is divided, as said above, into two portions k, of which one is connected with the repose-point d of the switch of the subscriber 1-2, to whom the strip belongs, and the other is connected by the return line-wire 3 with this su'bscribers station. Telephonic communication is therefore established between the two subscribers 1-1 and 1-2, and the subscriber 1-1 can call up the subscriber 1-2 by means of positive currents which do not change the positions of the devices of the exchange. These currents cannot reach the electromagnet E, because the arm D is not in contact with the point al of the switch-sector 1),, and all the other polarized electromagnets of the exchange act upon their armatures only when influenced by negative currents, except the electromagnet A,,. The electromagnet A belonging to the calling subscriber l-l may be operated by the positive currents used in calling or conversation, for at this time the lever 19 of the switch A is on the point I), but the action of the positive currents on the electromagnet A, can only produce rotation of the counting-wheels, an inconvenience of secondary consideration, and one, moreover, which can be avoided by taking the trouble of holding these wheels by any appropriate means before calling or speaking with the subscriber with whom communication has been established.

The positive calling-currents, or those employed in the operation of the telephone proper, neither of them produce any operation of the parts of the switch D belonging to the subscriber 1-2, with whom the subscriber 11 talks. These currents reach the repose-points d of the switch D of the subscriber 1- by the wire 15, pass to the brush 6, and thence to the line of subscriber 1-2, over which they reach his station, there to produce the call desired, they returning by the return line-wire 3, portion 7a, of the strip, and part i of the subscriber 1-1. At this time no other subscriber can put himself in communication with the subscriber 12, because the strip which corresponds with the latter subscriber is depressed by the carriage corresponding with the subscriber 1-1 in the group 1. Conversation ended, it is necessary to bring back the parts displaced to their original positions. The subscriber 1-1, who was the calling subscriber, operates the arm I) of his home switch in such a'inanner as to make it pass from the point I), to the point h and in passing to rub upon the point b The contact of the arm b-with the point I), sends, as above explained, anegative current to line. This negative current goes by the wire 2, the wire 14, to the arm D of the switch of subscriber 1-1, passes thence by the brush 6 to sector D and then divides into two currents, of which one, going by way of the brush 6 and ring D, traverses the electromagnet E, to return by the wire 15 and wire 3 to the station of subscriber 1-1, and the other, going by way of the binding-post e, of sector D and the latter to shift the system of the two wheels h and h and bring the wheel 77/ in contact with the wheel h This latter then turns in the opposite direction to that in which it revolved in advancing the carriage H This then runs back, and in reaching its startingpoint it strikes against the end of the bent lever H and thereby brings the system of wheels h h back to the middle position, so that carriage H stops and remains at rest. The negative current last referred to,which is produced by the passage of the arm I) of switch A over the point b of the home apparatus of subscriber 1-1, is divided, as has been seen, into. two, of which one traverses the electromagnet E and the other the electromagnet 71 but, further than this, the current goes by the wire 14: and the wire 19 to the portion 2 of the arm 1,, and from there it passes to thestrip before its separation from the arm 1 and by said strip and connections to the central-office switch of the subscriber 1-2. The negative current on traversing the electr'omagnet E of this switch forces the arm D to place itself on the part we of the first sector D. At this moment, that is to say, after the sending of the last negative current by the manipulation of the switch A of the substation 1-1, the parts occupy the following positions:

First. At the station of subscriber 1-1 the arm d of switch A is in notch No. 1. It has not budged. The arm I) of the switch A is at its 'startingpoint, and the wheels A A A are in the position of repose.

Second. At the central-office switch of subscriber 1-1 the arm D is on the part m of the sector D Third. In the first carriage group the carriage belonging to subscriber 1-1 is in the position of repose, ready for a new connection.

Fourth. At the central-oflice switch of the subscriber 1-2, with whom the subscriber 1-1 has been talking, the arm D is on the part on of sector D Fifth. At substation 1'2 none of the devices have changed place. All are in the repose positions.

It suiiices then for all the parts to be brought to zero that the arms D" of the two switches be returned to their repose-points. Thisis easily effected, and it suffices for each subscriber to turn the arm a of his home switch A from left to right until this arm reaches its repose position. This operation has for its object to send to each switch as many positive currents as there are contacts with metallic points a of the switches A hen the arm (1 of one of the switches A comes into contact with one of the switch-points thereof, a positive current from the battery A reaches the respective point by the wire 4, and after traversing the arm 61 goes thence by the wires 1, 2, and 14 to the switch D. If now consideration is given first to the arm D of the switch D of subscriber l1 which is on the part on d of the sector D it will be seen that the first positive current will reach the point (Z through the brush 6 and will thence pass to the electromagnet E, to return by the wires 15, 3, and 5 to the battery A The electromagnet E being traversed by a positive current attracts its armature, and the bar G, through the intermediary of the pawl G, turns the ratchet-wheel G through an are equal to three teeth, so that the arm D will come from the point (7 onto the point (1 of sector D for the displacements of the arm D produced by the electromagnet E are three times as large as those produced by the electromagnet E. If the subscriber 1-1 continues to operate the arm a, of his switch A the arm D will continue to step progressively from point d to point (1,, from point cl to point d and so on until it passes from point (Z to the reposepoint (i. It will then budge no farther, for this point is not connected with the electromagnet E. All the parts of substation 1-1 will thus have been brought to zero when this subscriber shall have effected a complete rotation of the arm (1,, of his switch A W hat has just been said of the subscriber 1-1 applies also to the subscriber 1-2, and the manipulation of the arm a of his switch A will in like manner bring the arm D" of his switch onto the repose-point. All the operations are now ended.

In the example just given the subscriber 1-1 is supposed to talk with the subscriber 1--2, who belonged to the same group as himself.

A case will now be taken in which the sub scriber 1l wishes to talk with a subscriber 52, for example, belonging to group No. 5. The same functions and effects are produced in the same manner as in the preceding example, and to follow them it is sufficient to refer to Figs. 11 and 11", on which the scheme of communication between these two subscribers is represented. The only difference in the manipulation in this case is in the op eration of the arm a of his switch A by the subscriber 11, an operation which he did not have to make in the first case because the two subscribers belonged to the same group. As mentioned above, after the sending of the negative currents for shifting the arm D from its repose position the subscriber 1-l should operate his switch A so as to place the arm D of the switch D on the sector corresponding with the group in which the subscriber is with whom he wishes to talk. In the example selected this subscriber belongs to the fifth group. He will have then to shift the arm (1 in such manner as to bring it between the metallic contacts 5 and 6. By this means he sends five positive currents, and thereby shifts the arm D" of his switch onto the part (1 of the sector D thus making a connection between the switch and the carriage of the subscriber 1-1 in group No. 5. From now on the same operations as in the first case are performed in the same way and in the same order.

The following is a resume of what a subscriber has to do in order to put himself in communication with another subscriber of the exchange:

First. The negative currents are sent by the switch A in order to shift the arm D of the central-office switch from its repose position to the point (1 of the first sector D Second. A series of positive currents is sent by the switch A in order to place the arm D of the switch on the first part of the sector corresponding with the group to which belongs the subscriber with whom it is wished to talk.

Third. The arms 0 of the counting-wheels are arranged according to the number in order of the last-mentioned subscriber in the group selected.

Fourth. A negative current is sent by the switch A to start the subscribers carriage in the selected group. After this current is sent the carriage in advancing sends to the callin g subscribers station positive currents, which traverse the electromagnet A and move the counting-wheels A A A Fifth. The arms C of the counting-wheels in reaching their positions of repose send to the central ol'fice a negative current, which stops the carriage. It is at this time that conversation can be carried on between the subscribers.

Sixth. A negative current is sent by the switch A from the station of the callingsubscriber. This current has the effect of bringin g back the carriage to its original position.

Seventh. The arms (1 of the two substationswitches A are rotated completely, so as to bring all the parts back to the repose positions.

In claiming the new or improved system of automatic switching for telephones whereby the services of employees at the central office for connecting the different subscribers with one another may be dispensed with, as also the various new or improved parts, arrangements,-or combinations forming parttherethat it stops. over the strip corresponding of, it will of course be understood that it is intended to secure the invention and each of the improvements constituting the same for all the applications of which they may severally or together be susceptible.

Iclaim as my invention or,discovery'- 1. An automatic systemv of telephoneswitching in which the station of each subscriber is connected with a central otfice switch divided into as many sectors as there are groups of subscribers andin which each sector of said centralbffice switch is connect} ed with a carriage that passes over strips connected respectively with the subscribers lines and is arranged to put itself in electrical connection with any given strip according to its position, the exchange being thus divided into groups in each of which there are as many carriages as there are subscribers to the exchange and as many strips as there are subscribers in that group, substantiallyas described.

2. An apparatus for a subscribers station comprising (in addition to the telephone instruments proper) a switch arranged to send to line positive currents, a second switch arranged to send negative currents to line, a counter composed of a number of wheels, and an electromagnet arranged in a branch which is closed by said second switch and having its armature connected with said counter,in combination with a central-office switch responding to negative and to positive currents, and arranged to connect the subscribers line with wires which lead from different divisions of said office-switch substantially as described.

3. An apparatus for a subscribers station comprising (in addition to the telephone instruments proper) a switch arranged to send to line positive currents, a second switch arranged to send negative currents to line, a counter composed of a number of wheels, and an electromagnet. arranged in a branch which is closed by said second switch and llEtV. ing its armature connected with said counter, in combination with a central-oflice switch responding to negative and to positive currents and arranged to connect the subscribers line with the wires that lead from the diiterent sectors, and electrical devices responding to negative currents, and arranged to put said wires in electrical connections with other subscribers lines, substantially as described. 4. In combination with the other parts of an automatic system of telephone-switching in which the station of each subscriber is connected with a central-office switch divided into as many sectors as there are groups of subscribers and in which each sector of said office-switch is connected with a carriage that passes over strips connected respectively with the subscribers lines and is arranged to put itself in electrical connection with any given strip according to its position, a counter at a subscribers station arranged to control the carriage belonging to such station so with the subscriber to be called, said counter being composed of a series of wheels with adjustable arms which can be set in a position to represent the number of the subscriber to be called and which being carried along with the wheels conjoin. in sending to line a current to arrest the carriage at the central office substantially as described.

5. A coun ter composed of ,a series of wheels provided with adjustable arms, switch-points and connection for completing a circuit through the arms in series, and an electromagnet operating means for turning the wheels, substantially as described.

6.- A counter composed of a series of wheels provided with adjustable arms, switch-points and connection for completing a circuit through the arms in series, and an electromagnetic operating means for turning the wheels, in combination with an automatic switching apparatus at the central office arranged to send currents to the subscribers station for turning said wheels and to be arrested by a current sent out by the conjoint action of said series of arms, substantially as described. 1

7. A switch having two electromagnets for turning its switch-arm, and two sets of switchpoints, one set of points being arranged for establishing the circuit through one of said electromagnets and the other for establishing connections with devices outside the switch, and movable circuit-closin g means contacting with a member of each set of switch-points in one position and with a member of but one set of switch-points in another position, whereby the circuit is simultaneously closed through one of said magnets and said outside devices in one position of the circuitclosing means, and through said outside de vices solely in the other position, substantially as described.

8. A switch having two electromagnets for turningits switch-arm, and two sets of s witchpoints, oneset of points being arranged for establishing the circuit through one of said electromagnets and the other for establishing connections with devices outside the switch, in combination with electromagnetically-controlled switching devices responding tocurrents of opposite polarity to those which actuate the last-mentioned electromagnet and arranged in the branches which are connected with the last-mentioned set of switch-points, substantially as described.

9. In combination with the other parts of an automatic system of telephone-switching in which the station of each subscriber is connected with a central-office switch divided into as many sectors as there are groups of subscribers and in which each sector of said office-switch is connected with a carriage that passes over strips connected respectively with the subscribers lines and is arranged to put itself in electrical connection with any given strip according to its position, a con tral-office switch having a switch-arm connected with the subscribers line and two polarized electromagnets responding to positive and negative currents respectively for turning said arm and the said switch being provided with a sector of repose and two additional sets of switch-points, of which one set is connected with the positive electromagnet aforesaid and the others with the respective electromagnets which control the carriages belonging to the subscriber in the several groups, substantially as described.

10. In the herein-described automatic system of telephone-switching, wherein each subscriber is provided at the central office with a movable carriage for effecting the desired connections, the central-office switch for each subscriber connected with the subscribers station by wires leading respectively through the arm of said switch and through two electromagnets of opposite polarity whose armatures operate ratchet-wheels that turn the said arm, the plate of said switch carrying two concentric metallic rings of which one is connected with the said negative electromagnet while the other divided into ten insulated two-part sectors and a sector of onethird the width has one insulated part of each of the ten sectors connected with the said positive electromagnet and the other insulated part with one or other of the electromagnets which control the movements of the corresponding carriages, and the said switcharm being provided with two brushes one of which is connected with the line and rubs over the sectors and the other of which is insulated and rubs over the ring and a part of the sectors, substantially as described.

11. A carriage system comprising an electromagnet arranged to control a system of bevel-wheels on a con tinuously-rotatin g shaft so that they are both out of contact with a third wheel or separately intermesh therewith according to their position, a screw connected with said third wheel and provided with a nut which constitutes or forms part of the carriage, an arm of said carriage, and strips which are depressed by said arm in passing and rise when it has passed, the said carriage not being arrested by the contact of said arms with the strips but continuing to advance and carrying a brush which during the depressions of the strips makes contact with a series of metallic points equal in number to the strips so as to close each time the circuit of a battery and send a positive current, substantially as described.

12. In combination with the other parts of an automatic system for telephone-switching in which the station of each subscriber is connected with a central-office switch divided into as many sectors as there are groups of subscribers and in which there is a counter at each subscribers station, a carriage system .corresponding with each sector of the respective switches and comprising an electromagnetarranged to control a system' of bevelwheels on a continuously-rotating shaft so that they are both out of contact \vitha third wheel or separately intermesh therewith according to their position, a screw connected with said third wheel and provided with a nut which constitutes or forms part of the carriage, an arm of said carriage, and strips which are depressed by said arm in passing and rise when it has passed, the said carriage not being arrested by the contact of said arms with the strips but continuing to advance and carrying a brush which during the depressions of the strips makes contact with a series of metallic points equal in number to the strips so as to close each time the circuit of a battery and send a positive current to the subscribers station for operating the counter there, substantially as described.

13. An automatic system for telephoneswitch in which the apparatus at each subscribers station is composed of a series of wheels with adjustable switch-arms, means whereby a current may be sent to line by the conjoint action of the series of arms, apolarized electromagnet for operating said wheels, and means whereby at one time positive and at another negative currents may be sent to the central office independently of said adj ustable arms, and whereby said polarized electromagnet may be connected in circuit at a particular time, and the apparatus at the central office is composed of groups of strips connected with different subscribers lines, carriages for all the subscribers, one for each, arranged to pass over the strips of each group for establishing electrical connection with any desired strip in such group, means whereby the said carriage may be controlled by currents from the subscribers station and may send currents to said station for operating the aforesaid series of wheels and switch-arms, and an electromagnet-switch for putting the subscribers line in connection with a carriage in one or other of said groups according to the position of said switch, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

MOISE FREUDENBERG. Vitnesses:

H. T. SMITH, EDOUARD BARBARY.

IIO 

